Removes all legacy wallet specific functional tests.
Also removes the --descriptor and --legacy-wallet options as these are
no longer necessary with the legacy wallet removed.
Behavior changes are:
- if a tx has a mempool conflict, the wallet will not attempt to
rebroadcast it
- if a txo is spent by a mempool-conflicted tx, that txo is no
longer considered spent
Test the case of a tx being conflicted by multiple
txs with different depths. The conflicted tx is also spent by
a child tx for which confirmation status is tied to the parent's.
After a reorg of conflicting txs, the conflicted status should be
undone properly.
Co-authored-by: furszy <mfurszy@protonmail.com>